DESCRIPTION

Text::CSV provides facilities for the composition and decomposition of comma-separated values using Text::CSV_XS or its pure Perl version.

An instance of the Text::CSV class can combine fields into a CSV string and parse a CSV string into fields.

The module accepts either strings or files as input and can utilize any user-specified characters as delimiters, separators, and escapes so it is perhaps better called ASV (anything separated values) rather than just CSV.

VERSION

1.33

This module is compatible with Text::CSV_XS 1.02 and later. (except for diag_verbose)

Embedded newlines

Important Note: The default behavior is to only accept ASCII characters. This means that fields can not contain newlines. If your data contains newlines embedded in fields, or characters above 0x7e (tilde), or binary data, you *must* set binary => 1 in the call to new (). To cover the widest range of parsing options, you will always want to set binary.

But you still have the problem that you have to pass a correct line to the parse () method, which is more complicated from the usual point of usage:

On combining (print () and combine ()), if any of the combining fields was marked UTF8, the resulting string will be marked UTF8.

Note however if the backend module is Text::CSV_XS, that all fields before the first field that was marked UTF8 and contained 8-bit characters that were not upgraded to UTF8, these will be bytes in the resulting string too, causing errors. If you pass data of different encoding, or you don't know if there is different encoding, force it to be upgraded before you pass them on:

SPECIFICATION

FUNCTIONS

These methods are common between the XS and the pure Perl version. Most of the document was shamelessly copied and replaced from Text::CSV_XS.

version ()

(Class method) Returns the current backend module version. If you want the module version, you can use the VERSION method,

print Text::CSV->VERSION; # This module version
print Text::CSV->version; # The version of the worker module
# same as Text::CSV->backend->version

new (\%attr)

(Class method) Returns a new instance of Text::CSV_XS. The objects attributes are described by the (optional) hash ref \%attr. Currently the following attributes are available:

eol

An end-of-line string to add to rows. undef is replaced with an empty string. The default is $\. Common values for eol are "\012" (Line Feed) or "\015\012" (Carriage Return, Line Feed). Cannot be longer than 7 (ASCII) characters.

If both $/ and eol equal "\015", parsing lines that end on only a Carriage Return without Line Feed, will be parsed correct. Line endings, whether in $/ or eol, other than undef, "\n", "\r\n", or "\r" are not (yet) supported for parsing.

sep_char

The char used for separating fields, by default a comma. (,). Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The separation character can not be equal to the quote character. The separation character can not be equal to the escape character.

When this option is set to true, whitespace (TAB's and SPACE's) surrounding the separation character is removed when parsing. If either TAB or SPACE is one of the three major characters sep_char, quote_char, or escape_char it will not be considered whitespace.

So lines like:

1 , "foo" , bar , 3 , zapp

are now correctly parsed, even though it violates the CSV specs.

Note that all whitespace is stripped from start and end of each field. That would make it more a feature than a way to be able to parse bad CSV lines, as

1, 2.0, 3, ape , monkey

will now be parsed as

("1", "2.0", "3", "ape", "monkey")

even if the original line was perfectly sane CSV.

blank_is_undef

Under normal circumstances, CSV data makes no distinction between quoted- and unquoted empty fields. They both end up in an empty string field once read, so

1,"",," ",2

is read as

("1", "", "", " ", "2")

When writing CSV files with always_quote set, the unquoted empty field is the result of an undefined value. To make it possible to also make this distinction when reading CSV data, the blank_is_undef option will cause unquoted empty fields to be set to undef, causing the above to be parsed as

("1", "", undef, " ", "2")

empty_is_undef

Going one step further than blank_is_undef, this attribute converts all empty fields to undef, so

1,"",," ",2

is read as

(1, undef, undef, " ", 2)

Note that this only effects fields that are really empty, not fields that are empty after stripping allowed whitespace. YMMV.

quote_char

The char used for quoting fields containing blanks, by default the double quote character ("). A value of undef suppresses quote chars. (For simple cases only). Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The quote character can not be equal to the separation character.

allow_loose_quotes

By default, parsing fields that have quote_char characters inside an unquoted field, like

1,foo "bar" baz,42

would result in a parse error. Though it is still bad practice to allow this format, we cannot help there are some vendors that make their applications spit out lines styled like this.

In case there is really bad CSV data, like

1,"foo "bar" baz",42

or

1,""foo bar baz"",42

there is a way to get that parsed, and leave the quotes inside the quoted field as-is. This can be achieved by setting allow_loose_quotesAND making sure that the escape_char is not equal to quote_char.

escape_char

The character used for escaping certain characters inside quoted fields. Limited to a single-byte character, usually in the range from 0x20 (space) to 0x7e (tilde).

The escape_char defaults to being the literal double-quote mark (") in other words, the same as the default quote_char. This means that doubling the quote mark in a field escapes it:

"foo","bar","Escape ""quote mark"" with two ""quote marks""","baz"

If you change the default quote_char without changing the default escape_char, the escape_char will still be the quote mark. If instead you want to escape the quote_char by doubling it, you will need to change the escape_char to be the same as what you changed the quote_char to.

The escape character can not be equal to the separation character.

allow_loose_escapes

By default, parsing fields that have escape_char characters that escape characters that do not need to be escaped, like:

would result in a parse error. Though it is still bad practice to allow this format, this option enables you to treat all escape character sequences equal.

binary

If this attribute is TRUE, you may use binary characters in quoted fields, including line feeds, carriage returns and NULL bytes. (The latter must be escaped as "0.) By default this feature is off.

If a string is marked UTF8, binary will be turned on automatically when binary characters other than CR or NL are encountered. Note that a simple string like "\x{00a0}" might still be binary, but not marked UTF8, so setting { binary => 1 } is still a wise option.

decode_utf8

This attributes defaults to TRUE.

While parsing, fields that are valid UTF-8, are automatically set to be UTF-8, so that

$csv->parse ("\xC4\xA8\n");

results in

PV("\304\250"\0) [UTF8 "\x{128}"]

Sometimes it might not be a desired action. To prevent those upgrades, set this attribute to false, and the result will be

PV("\304\250"\0)

types

A set of column types; this attribute is immediately passed to the types method below. You must not set this attribute otherwise, except for using the types method. For details see the description of the types method below.

always_quote

By default the generated fields are quoted only, if they need to, for example, if they contain the separator. If you set this attribute to a TRUE value, then all defined fields will be quoted. This is typically easier to handle in external applications.

quote_space

By default, a space in a field would trigger quotation. As no rule exists this to be forced in CSV, nor any for the opposite, the default is true for safety. You can exclude the space from this trigger by setting this option to 0.

quote_null

By default, a NULL byte in a field would be escaped. This attribute enables you to treat the NULL byte as a simple binary character in binary mode (the { binary => 1 } is set). The default is true. You can prevent NULL escapes by setting this attribute to 0.

quote_binary

By default, all "unsafe" bytes inside a string cause the combined field to be quoted. By setting this attribute to 0, you can disable that trigger for bytes >= 0x7f.

keep_meta_info

By default, the parsing of input lines is as simple and fast as possible. However, some parsing information - like quotation of the original field - is lost in that process. Set this flag to true to be able to retrieve that information after parsing with the methods meta_info (), is_quoted (), and is_binary () described below. Default is false.

verbatim

This is a quite controversial attribute to set, but it makes hard things possible.

The basic thought behind this is to tell the parser that the normally special characters newline (NL) and Carriage Return (CR) will not be special when this flag is set, and be dealt with as being ordinary binary characters. This will ease working with data with embedded newlines.

When verbatim is used with getline (), getline () auto-chomp's every line.

Imagine a file format like

M^^Hans^Janssen^Klas 2\n2A^Ja^11-06-2007#\r\n

where, the line ending is a very specific "#\r\n", and the sep_char is a ^ (caret). None of the fields is quoted, but embedded binary data is likely to be present. With the specific line ending, that should not be too hard to detect.

By default, Text::CSV' parse function however is instructed to only know about "\n" and "\r" to be legal line endings, and so has to deal with the embedded newline as a real end-of-line, so it can scan the next line if binary is true, and the newline is inside a quoted field. With this attribute however, we can tell parse () to parse the line as if \n is just nothing more than a binary character.

For parse () this means that the parser has no idea about line ending anymore, and getline () chomps line endings on reading.

auto_diag

Set to true will cause error_diag () to be automatically be called in void context upon errors.

If set to a value greater than 1, it will die on errors instead of warn.

print

$status = $csv->print ($io, $colref);

Similar to combine () + string () + print, but more efficient. It expects an array ref as input (not an array!) and the resulting string is not really created (XS version), but immediately written to the $io object, typically an IO handle or any other object that offers a print method. Note, this implies that the following is wrong in perl 5.005_xx and older:

open FILE, ">", "whatever";
$status = $csv->print (\*FILE, $colref);

as in perl 5.005 and older, the glob \*FILE is not an object, thus it does not have a print method. The solution is to use an IO::File object or to hide the glob behind an IO::Wrap object. See IO::File and IO::Wrap for details.

For performance reasons the print method doesn't create a result string. (If its backend is PP version, result strings are created internally.) In particular the $csv->string (), $csv->status (), $csv-fields ()> and $csv->error_input () methods are meaningless after executing this method.

combine

$status = $csv->combine (@columns);

This object function constructs a CSV string from the arguments, returning success or failure. Failure can result from lack of arguments or an argument containing an invalid character. Upon success, string () can be called to retrieve the resultant CSV string. Upon failure, the value returned by string () is undefined and error_input () can be called to retrieve an invalid argument.

string

$line = $csv->string ();

This object function returns the input to parse () or the resultant CSV string of combine (), whichever was called more recently.

getline

$colref = $csv->getline ($io);

This is the counterpart to print, like parse is the counterpart to combine: It reads a row from the IO object $io using $io->getline () and parses this row into an array ref. This array ref is returned by the function or undef for failure.

When fields are bound with bind_columns (), the return value is a reference to an empty list.

getline_all

This will return a reference to a list of getline ($io) results. In this call, keep_meta_info is disabled. If $offset is negative, as with splice (), only the last abs ($offset) records of $io are taken into consideration.

parse

$status = $csv->parse ($line);

This object function decomposes a CSV string into fields, returning success or failure. Failure can result from a lack of argument or the given CSV string is improperly formatted. Upon success, fields () can be called to retrieve the decomposed fields . Upon failure, the value returned by fields () is undefined and error_input () can be called to retrieve the invalid argument.

You may use the types () method for setting column types. See the description below.

getline_hr

The getline_hr () and column_names () methods work together to allow you to have rows returned as hashrefs. You must call column_names () first to declare your column names.

Will set $hr-{"\cAUNDEF\cA"}> to the 1st field, $hr-{""}> to the 2nd field, and $hr-{name}> to the 4th field, discarding the 3rd field.

column_names () croaks on invalid arguments.

bind_columns

Takes a list of references to scalars to store the fields fetched getline () in. When you don't pass enough references to store the fetched fields in, getline () will fail. If you pass more than there are fields to return, the remaining references are left untouched.

eof

$eof = $csv->eof ();

If parse () or getline () was used with an IO stream, this method will return true (1) if the last call hit end of file, otherwise it will return false (''). This is useful to see the difference between a failure and end of file.

types

$csv->types (\@tref);

This method is used to force that columns are of a given type. For example, if you have an integer column, two double columns and a string column, then you might do a

Column types are used only for decoding columns, in other words by the parse () and getline () methods.

You can unset column types by doing a

$csv->types (undef);

or fetch the current type settings with

$types = $csv->types ();

IV

Set field type to integer.

NV

Set field type to numeric/float.

PV

Set field type to string.

fields

@columns = $csv->fields ();

This object function returns the input to combine () or the resultant decomposed fields of C successful <parse ()>, whichever was called more recently.

Note that the return value is undefined after using getline (), which does not fill the data structures returned by parse ().

meta_info

@flags = $csv->meta_info ();

This object function returns the flags of the input to combine () or the flags of the resultant decomposed fields of parse (), whichever was called more recently.

For each field, a meta_info field will hold flags that tell something about the field returned by the fields () method or passed to the combine () method. The flags are bit-wise-or'd like:

0x0001

The field was quoted.

0x0002

The field was binary.

See the is_*** () methods below.

is_quoted

my $quoted = $csv->is_quoted ($column_idx);

Where $column_idx is the (zero-based) index of the column in the last result of parse ().

This returns a true value if the data in the indicated column was enclosed in quote_char quotes. This might be important for data where ,20070108, is to be treated as a numeric value, and where ,"20070108", is explicitly marked as character string data.

is_binary

my $binary = $csv->is_binary ($column_idx);

Where $column_idx is the (zero-based) index of the column in the last result of parse ().

This returns a true value if the data in the indicated column contained any byte in the range [\x00-\x08,\x10-\x1F,\x7F-\xFF]

is_missing

my $missing = $csv->is_missing ($column_idx);

Where $column_idx is the (zero-based) index of the column in the last result of "getline_hr".

while (my $hr = $csv->getline_hr ($fh)) {
$csv->is_missing (0) and next; # This was an empty line
}

When using "getline_hr" for parsing, it is impossible to tell if the fields are undef because they where not filled in the CSV stream or because they were not read at all, as all the fields defined by "column_names" are set in the hash-ref. If you still need to know if all fields in each row are provided, you should enable keep_meta_info so you can check the flags.

status

$status = $csv->status ();

This object function returns success (or failure) of combine () or parse (), whichever was called more recently.

error_input

$bad_argument = $csv->error_input ();

This object function returns the erroneous argument (if it exists) of combine () or parse (), whichever was called more recently.

error_diag

If (and only if) an error occurred, this function returns the diagnostics of that error.

If called in void context, it will print the internal error code and the associated error message to STDERR.

If called in list context, it will return the error code and the error message in that order. If the last error was from parsing, the third value returned is the best guess at the location within the line that was being parsed. It's value is 1-based.

Note: $pos returned by the backend Text::CSV_PP does not show the error point in many cases (see to the below line). It is for conscience's sake in using Text::CSV_PP.

If called in scalar context, it will return the diagnostics in a single scalar, a-la $!. It will contain the error code in numeric context, and the diagnostics message in string context.

Depending on the used worker module, returned diagnostics is different.

Text::CSV_XS parses csv strings by dividing one character while Text::CSV_PP by using the regular expressions. That difference makes the different cause of the failure.

When called as a class method or a direct function call, the error diag is that of the last new () call.

record_number

$recno = $csv->record_number ();

Returns the records parsed by this csv instance. This value should be more accurate than $. when embedded newlines come in play. Records written by this instance are not counted.

SetDiag

$csv->SetDiag (0);

Use to reset the diagnostics if you are dealing with errors.

Some methods are Text::CSV only.

backend

Returns the backend module name called by Text::CSV. module is an alias.

is_xs

Returns true value if Text::CSV or the object uses XS module as worker.

is_pp

Returns true value if Text::CSV or the object uses pure-Perl module as worker.

DIAGNOSTICS

If an error occurred, $csv->error_diag () can be used to get more information on the cause of the failure. Note that for speed reasons, the internal value is never cleared on success, so using the value returned by error_diag () in normal cases - when no error occurred - may cause unexpected results.

HISTORY AND WORKER MODULES

This module, Text::CSV was firstly written by Alan Citterman which could deal with only ascii characters. Then, Jochen Wiedmann wrote Text::CSV_XS which has the binary mode. This XS version is maintained by H.Merijn Brand and Text::CSV_PP written by Makamaka was pure-Perl version of Text::CSV_XS.

Now, Text::CSV was rewritten by Makamaka and become a wrapper to Text::CSV_XS or Text::CSV_PP. Text::CSV_PP will be bundled in this distribution.

When you use Text::CSV, it calls a backend worker module - Text::CSV_XS or Text::CSV_PP. By default, Text::CSV tries to use Text::CSV_XS which must be complied and installed properly. If this call is fail, Text::CSV uses Text::CSV_PP.

The required Text::CSV_XS version is 0.41 in Text::CSV version 1.03.

If you set an environment variable PERL_TEXT_CSV, The calling action will be changed.

PERL_TEXT_CSV = 0

PERL_TEXT_CSV = 'Text::CSV_PP'

Always use Text::CSV_PP

PERL_TEXT_CSV = 1

PERL_TEXT_CSV = 'Text::CSV_XS,Text::CSV_PP'

(The default) Use compiled Text::CSV_XS if it is properly compiled & installed, otherwise use Text::CSV_PP

SEE ALSO

AUTHORS and MAINTAINERS

Alan Citterman <alan[at]mfgrtl.com> wrote the original Perl module. Please don't send mail concerning Text::CSV to Alan, as he's not a present maintainer.

Jochen Wiedmann <joe[at]ispsoft.de> rewrote the encoding and decoding in C by implementing a simple finite-state machine and added the variable quote, escape and separator characters, the binary mode and the print and getline methods. See ChangeLog releases 0.10 through 0.23.

H.Merijn Brand <h.m.brand[at]xs4all.nl> cleaned up the code, added the field flags methods, wrote the major part of the test suite, completed the documentation, fixed some RT bugs. See ChangeLog releases 0.25 and on.

Makamaka Hannyaharamitu, <makamaka[at]cpan.org> wrote Text::CSV_PP which is the pure-Perl version of Text::CSV_XS.